(statistics) the probability of rejecting the null hypothesis in a test when it is false. The power of a test of a given null depends on the particular alternative hypothesis against which it is tested

12.

(physics, engineering) a measure of the rate of doing work expressed as the work done per unit time. It is measured in watts, horsepower, etc P

13.

the rate at which electrical energy is fed into or taken from a device or system. It is expressed, in a direct-current circuit, as the product of current and voltage and, in an alternating-current circuit, as the product of the effective values of the current and voltage and the cosine of the phase angle between them. It is measured in watts

(as modifier): a power amplifier

14.

the ability to perform work

15.

mechanical energy as opposed to manual labour

(as modifier): a power mower

16.

a particular form of energy: nuclear power

17.

a measure of the ability of a lens or optical system to magnify an object, equal to the reciprocal of the focal length. It is measured in dioptres

Whatever some hypocritical ministers of government may say about it, power is the greatest of all pleasures. It seems to me that only love can beat it, and love is a happy illness that can't be picked up as easily as a Ministry. [Stendhal "de l'Amour," 1822]

Meaning "one who has power" is late 14c. Meaning "specific ability or capacity" is from early 15c. Meaning "a state or nation with regard to international authority or influence" [OED] is from 1726. Used for "a large number of" from 1660s. Meaning "energy available for work is from 1727. Sense of "electrical supply" is from 1896.

Phrase the powers that be is from Rom. xiii:1. As a statement wishing good luck, more power to (someone) is recorded from 1842. A power play in ice hockey so called by 1940. Power failure is from 1911; power steering from 1921.

The rate at which work is done, or energy expended, per unit time. Power is usually measured in watts (especially for electrical power) or horsepower (especially for mechanical power). For a path conducting electrical current, such as a component in an electric circuit, P = VI, where P is the power dissipated along the path, V is the voltage across the path, and I is the current through the path. Compare energy, work.

Mathematics The number of times a number or expression is multiplied by itself, as shown by an exponent. Thus ten to the sixth power, or 106, equals one million.

A number that represents the magnification of an optical instrument, such as a microscope or telescope. A 500-power microscope can magnify an image to 500 times its original size.

power definition

In mathematics, a power is a number multiplied by itself the number of times signified by an exponent placed to the right and above it. Thus, 32, which means 3 × 3, is a power — the second power of three, or three squared, or nine. The expression 106, or ten to the sixth power, means 10 × 10 × 10 × 10 × 10 × 10, or one million.